Does Hunting Affect the Behavior of Wild Pigs?

Wild boar and feral swine (Sus scrofa) numbers are growing worldwide. In parallel, their severe ecological and economic impacts are also increasing and include vehicle collisions, damage to crops and amenities, reduction in plant and animal abundance and richness, and transmission of diseases, the latter causing billions of U.S. dollars in losses to the livestock industry each year. Recreational hunters are the main cause of mortality for this species, and hunting has traditionally been the main method to contain populations of wild pigs. Hunting might affect the behavior of the species, which potentially can lead to these animals moving to new areas or to an increase in disease transmission. This review summarized the evidence that recreational hunting influences the behavior of wild pigs. Twenty-nine studies reported the effect of recreational hunting on social, spatial, and temporal behavior. Although most found that recreational hunting caused changes in home range size, home range shifting, habitat use, and activity patterns, there was little agreement between studies on the size, direction, and duration of these effects. Several studies suggested that other factors, such as season and food availability, equally affect the behavior of this species. Very few studies provided details about the type and frequency of hunting, the number of hunters and dogs (Canis lupus familiaris), the number of animals harvested, or the presence of reserve areas where hunting was forbidden on neighboring sites. As wild pigs adapt to human disturbance, these factors should be investigated to minimize the effects of recreational hunting on the behavior of the species, particularly in the context of disease transmission

Stakeholder Acceptance of Wild Equid Fertility Control Mirrors Global Shifts in Attitudes to Wildlife Management

Wild equid (horses [Equus ferus] and burros [E. asinus]) populations have increased on public lands in the United States since the passage of the Wild Free-Roaming Horses and Burros Act of 1971. As of March 1, 2022, the Bureau of Land Management (BLM) estimated that wild equid populations on designated herd management areas (HMAs) may exceed 82,000 animals. In 2020, the total population of wild equids in the United States was estimated to exceed 300,000 animals. The BLM sets an appropriate management level (AML) for wild horse and burro herds on each HMA and removes animals when AMLs are exceeded. At present, the number of animals removed and placed in long-term holding is greater than the number adopted and sold. In 2021, the cost of caring for 59,000 animals in government holding facilities was \u3e$72 million USD. Although the management of wild equid populations remains controversial among stakeholders, fertility control has gained wider acceptance, with injectable immunocontraceptive vaccines already employed to manage herds. Contemporary stakeholder views of wild equid management decisions may also reflect global shifts in public attitudes to wildlife management. These attitudes are driving both decisions and innovations in alternative approaches, such as fertility control, to manage wildlife. In this context, the Botstiber Institute for Wildlife Fertility Control is acting as a catalyst to advance the use of effective, sustainable fertility control methods to mitigate human–wildlife conflicts and promote coexistence worldwide

Too Many Hogs? A Review of Methods to Mitigate Impact by Wild Boar and Feral Hogs

Feral hogs (Sus scrofa) are among the most widely-distributed mammals in the world and have the highest reproductive output compared with other ungulates. Worldwide, feral hogs are increasing in range and numbers. Human–feral hog conflicts include impact on abundance and richness of plant and animal species, crop damage, predation on livestock, vehicle collisions, and disease transmission. We reviewed methods employed to mitigate the impact of feral hogs on human activities and discussed these methods in terms of effectiveness, feasibility, costs, and social acceptance. Traditional methods of control include trapping, angering, shooting, poisoning, and Judas hogs. Nonlethal methods of control include fertility control, fencing, repellents, diversionary feeding, and translocation.The review indicated that successful eradications of feral hogs from islands have been achieved by combining different control methods and by establishing post-eradication monitoring to ascertain that the eradication had been completed. Conversely, on the mainland and in countries where feral hogs have long been established, management of human–feral hog conflicts often relies on population size reduction through hunting and poisoning the animals or on exclusion fencing and diversionary feeding. In the majority of instances, population control is not based on previous knowledge of local densities or on predicted impact of control on population size. Based on these results, we propose a framework of criteria to guide decisions regarding the suitability of different options to manage human–feral hog conflicts in different contexts

Novel Management Methods: Immunocontraception and Other Fertility Control Tools

Impacts of overabundant ungulate populations on human activities and conservation include crop and forestry losses, collisions with vehicles, disease transmission, nuisance behaviour, damage to infrastructures, predation on livestock and native species, and reduction of biodiversity in plant and animal communities (e.g. Curtis et ai., 2002; Massei et al., 2011; Reimoser and Putman, 2011; Ferroglio et ai., 2011; Langbein et al., 2011). Current trends in human population growth and landscape development indicate that human-ungulate conflicts in Europe, as well as in the United States, are likely to increase in parallel with increased expansion in numbers and range of many of these species (Rutberg and Naugle, 2008; Brainerd and Kaltenborn, 2010; Gionfriddo et aI., 2011 a). Many of these conflicts have been traditionally managed by lethal methods. However, current trends in distribution and numbers of wild boar, feral pigs and deer in Europe and in the United States (e.g. Saez-Royuela and Telleria, 1986; Waithman et ai., 1999; Ward, 2005; Apollonio et al., 2010) suggest that recreational hlllting is not sufficient to control ungulate densities. In addition, ethical considerations regarding humane treatment of animals are increasingly shaping public attitudes about what are considered acceptable methods of mitigating human-wildlife conflicts, and lethal control is often opposed (Beringer et al., 2002; Wilson, 2003; Barfield et al., 2006; McShea, 2012). Public antipathy towards lethal methods increasingly constrains the options available for ungulate management, particularly in urban and suburban areas and in protected areas where culling is often opposed on ethical, legal or safety grounds (Kirkpatrick et al., 2011; Boulanger et al., 2012; Rutberg et al., 2013). Consequently, interest in non-lethal methods, such as translocation or fertility control, has increased (Fagerstone et ai., 2010)

A Novel Method for Detecting Wild Boar Presence

Populations of wild boar and feral pigs (Sus scrofa) are increasing in numbers and distribution worldwide, in parallel with their significant environmental and economic impact. Reliable methods to detect the presence of this species are needed for monitoring its natural range expansion and its occurrence in areas where animals have been deliberately or accidentally introduced. The main aim of this study, carried out in English woodlands recently colonized by wild boar, was to assess the effectiveness of a birch wood tar-based compound, to detect the presence of this species in presence/absence surveys. A pilot trial in woodlands where wild boar had been established for circa 20 years found that wild boar sniffed and rubbed their bodies against stakes treated with this compound significantly more than against control stakes treated with water, thus confirming that the birch wood tar attracted wild boar to stakes. A second trial, carried out by applying the birch wood tar to trees in 8 woodlands surrounding the core range of wild boar, found that these animals left consistently more activity signs such as rubbing, tusk marks, and rooting on or around trees treated with this compound than on or around control trees treated with water. These results suggest that birch wood tar can be used as a method to confirm presence of wild boar in an area. Possible applications of this compound include its use to increase trapping efficiency or its deployment to confirm the success of a local eradication

Efficacy Of The Boar-Operated-System To Deliver Baits To Feral Swine.

Feral swine (Sus scrofa) pose a significant disease threat to livestock and humans. Emerging technologies to reduce feral swine disease transmission risks include fertility control, vaccination, and toxicants. However, for these technologies to be appropriate for field application, a feral swine-specific oral delivery system is needed. We used two field trials to generate information related to appropriate field application of the Boar-Operated-System (BOSTM), an oral delivery system designed to provide bait access only to feral swine. Our objectives were to determine whether pre-baiting BOSTM units increased bait removal and to evaluate the proportion of feral swine and non-target animals that ingest baits designed to deliver pharmaceuticals through the BOSTM. During both trials we used baits housed within 10 BOSTM units.Wemonitored wildlife visitation, bait removal, and ingestion using motion sensing digital photography and baits containing the bait marker tetracycline hydrochloride (TH). During trial 1 we found three of five pre-baited BOSTM units were used by feral swine only. Additionally, we found the five BOSTM units that were not pre-baited were not used by feral swine or non-target wildlife. During trial 2 we determined bait removal from the BOSTM to be reduced by only 10% for feral swine when activated, whereas bait removal from the BOSTM by all other wildlife was reduced by 100% when activated. We captured 81 feral swine and 23 raccoons and found 90% and 13% to have TH-marked teeth, respectively. With minor modifications, the BOSTM should be considered a valuable tool to be used in feral swine disease management in conjunction with existing technologies

Long-term effect of a GnRH-based immunocontraceptive on feral cattle in Hong Kong

Increasing human-wildlife conflicts worldwide are driving the need for multiple solutions to reducing “problem” wildlife and their impacts. Fertility control is advocated as a non-lethal tool to manage free-living wildlife and in particular to control iconic species. Injectable immunocontraceptives, such as GonaCon, stimulate the immune system to produce antibodies against the gonadotrophin-releasing hormone (GnRH), which in turn affects the release of reproductive hormones in mammals. Feral cattle (Bos indicus or Bos taurus) in Hong Kong are an iconic species whose numbers and impacts on human activities have increased over the last decade. Previous studies have proven that a primer vaccination and booster dose of GonaCon in female cattle are safe and effective in reducing pregnancy levels one year post-treatment. The aims of this project were 1. to evaluate the longevity of the effect of GonaCon in feral cattle up to four years post-vaccination; and 2. to assess if a second booster dose of GonaCon, administered at either two or four years post-vaccination, extends the contraceptive effect in this species. Vaccination with Gona- Con, administered as a primer and booster dose, was effective in causing significant infertility in free-living cattle for at least three years post-vaccination, with the percentage of pregnant animals in the vaccinated group decreasing from 76% at vaccination to 35%, 19% and 7% in years 2, 3 and 4 post-vaccination, compared with 67% at vaccination to 50%, 57% and 14% respectively in the control group. A second booster dose of GonaCon administered either 2 or 4 years after vaccination rendered 100% of the Treated cattle infertile for at least another year. These results suggested that vaccination with GonaCon can reduce feral cattle population growth and that a second booster dose can extend the longevity of the contraceptive effect

Long-term effect of a GnRH-based immunocontraceptive on feral cattle in Hong Kong

Increasing human-wildlife conflicts worldwide are driving the need for multiple solutions to reducing “problem” wildlife and their impacts. Fertility control is advocated as a non-lethal tool to manage free-living wildlife and in particular to control iconic species. Injectable immunocontraceptives, such as GonaCon, stimulate the immune system to produce antibodies against the gonadotrophin-releasing hormone (GnRH), which in turn affects the release of reproductive hormones in mammals. Feral cattle (Bos indicus or Bos taurus) in Hong Kong are an iconic species whose numbers and impacts on human activities have increased over the last decade. Previous studies have proven that a primer vaccination and booster dose of GonaCon in female cattle are safe and effective in reducing pregnancy levels one year post-treatment. The aims of this project were 1. to evaluate the longevity of the effect of GonaCon in feral cattle up to four years post-vaccination; and 2. to assess if a second booster dose of GonaCon, administered at either two or four years post-vaccination, extends the contraceptive effect in this species. Vaccination with Gona- Con, administered as a primer and booster dose, was effective in causing significant infertility in free-living cattle for at least three years post-vaccination, with the percentage of pregnant animals in the vaccinated group decreasing from 76% at vaccination to 35%, 19% and 7% in years 2, 3 and 4 post-vaccination, compared with 67% at vaccination to 50%, 57% and 14% respectively in the control group. A second booster dose of GonaCon administered either 2 or 4 years after vaccination rendered 100% of the Treated cattle infertile for at least another year. These results suggested that vaccination with GonaCon can reduce feral cattle population growth and that a second booster dose can extend the longevity of the contraceptive effect

Effect of vaccination with a novel GnRH-based immunocontraceptive on immune responses and fertility in rats

1. As human-wildlife conflicts increase worldwide, novel methods are required for mitigating these conflicts. Fertility control, based on immunocontraceptives, has emerged as an alternative option to lethal methods for managing wildlife. 2. Immunocontraceptives are vaccines that generate an immune response to key components of an animal\u27s reproductive system. Some of these vaccines target the gonadotropin-releasing hormone (GnRH) and have been used successfully as contraceptives for many wildlife species. However, the need to capture animals for treatment limits the field applications of injectable vaccines. The availability of orally delivered immunocontraceptives would increase the breadth of applications of fertility control for wildlife management. 3. This study explored a new approach to developing an oral immunocontraceptive, exploiting the bioadhesive and immunologically active properties of killed Mycobacterium avium cell wall fragments (MAF). The MAF was conjugated to a GnRH recombinant protein called IMX294, used as a GnRH-specific immunogen. 4. An initial trial using the MAF-IMX294 conjugate provided the first evidence that an orally delivered immunocontraceptive vaccine could generate anti-GnRH antibody titres in laboratory rats. 5. Increasing the dose and frequency of vaccine administered to rats, in a second trial, enhanced the immune response, eliciting titres that reduced the proportion of females giving birth. This provided the first evidence of the contraceptive effect of an oral anti-GnRH vaccine. 6. Future work is required to further increase the immunogenic effect of the oral vaccine and to establish a dosing schedule that is effective for practical field applications